I installed seat heaters in my 2003 wrx wagon. A popular misconception is that you can't put seat heaters in a car that dosent have leather seats. In reality you can put seat heaters in any seat.
I used Carbotex seat heaters for this install,http://www.cartekdist.com/
they are universal and can be cut to fit any seat. I used the Hi-Lo ones but they also sell a cheaper one temperture set.
list of tools you'll need:
14,12,10 mm sockets
hog ring pliers (not sure where you can get them, I got mine from a Snap-on truck.)
panel removal tool
5/8 hole saw or uni bit
list of supplies you'll need:
various types of wire connectors
about 10 FT. of 12-14 gauge wire
Lets begin by disconnecting the negitive battery cable
1. Remove the front 2 14 mm seat bolts.
2. Remove the rear 2 14 mm seat bolts.
3. Unplug the air bag wire (if you have it) Note, dont start the car with this wire unplugged
or it will turn on your airbag light in the dash, to get the light off disconnect the battery.
4. Remove the seat from the car.
5. Remove the 4 screws that hold the side cover on the seat, and remove that panel from the seat.
6. Remove the 2 12 mm bolts that hold the seat bottom to the seat.
7. Remove the 2 12 mm bolts on the other side that hold the seat bottom to the seat.
Now you can remove the seat bottom from the frame, the seat back will stay attached.
8. Turn the seat bottom upside down and remove the 2 hog rings (refer to pic for removal) and the 8 plastic clips that hold the fabric to the seat.
9. Flip seat over and proceed to remove the 7 hog rings that are shown in the picture.
there is no need to remove them all.
10. Place the heating element on the seat bottom an mark where to cut out for the listing rod.
11. cut the heating element so you can reattach the listing rod, The seat heaters I used are carbotex, they can be cut ,as log as you don't cut
into the 2 inches on the side that stick the element to the foam.
12. Stick the element to the foam and poke a hole in the foam for the wire to pass through to the bottom of the seat.
13. Reattach the the listing rods to the foam with new hog rings.
14. Flip seat back over a reattach the 2 hog rings and 8 clips. the seat bottom is now done but don't attach it to frame until you get the seat back done
now for the seat back.
15. Unzip the 2 zippers on the back of the seat back and remove the 3 clips on the bottom.
16. You only have to remove the 2 hog rings on the seat back because you dont have to cut the element on the seat back.
17. Peel the backing of the adhesive that holds the element to the seat and slide the element under the fabric and stick it to the foam.
18. Run the wire along side the airbag wire, if you dont have air bags the find a spot to run it so it dosent get pinched.
19. Attach 2 new hog rings and the 3 clips on the bottom and zip the zippers.
20. Attach the seat bottom with the 4 12 mm bolts that you removed.
21. Attach the side cover and the put the 4 phillips screws back in.
22. Connect the wires under the seat and zip tie them to the bottom of the seat so that the don't get pinched.
Now the elements are in the seat and the wires are all tied up, its time to mount the switch and run the wires. I chose to put the switches in the center consol next to the gear shifter you can really mount them anywhere.
1. Remove the lower panel under the steering wheel, 2 philips on the bottom and a plastic phillips on the side.
2. Now remove the 2 10 mm bolts tha hold the metal bracket on.
3. The seats need +12 volt switched so you dont leave them on by accident, find the switched wire with a test light and crimp the 12 guage wire to it. after
you have it crimped install a 30 amp fuse to the wire that goes from the ignition harness to under the seat.
4. Run the wire under the carpet to under each seat (there is a hundred different ways to do this) making sure the wire is not going to be pinched by anything.
5. Now put the dash back together the oppisite of removal.
Now time to mount the switches. Like I said, I put the switches in the center consol so this step will be different if you mount the switches somewhere else
6. Remove the shifter knob.
7. Remove the the shifter boot and plastic surround by pulling upward and releasing the clips that hold it on.
8. Once its removed mark the spots where the switches go, I used a hole saw which needs a 1/8 pilot hole drilled first so I did that.
9. Drill or rotozip the hole to the proper size.
10. Put switch in hole and route the wire to under the seat.
11. Now put the consol back together the oppisite of removal.
12. The last step in the wiring is to supply a ground to each seat, I just attached the ground wire to a piece of metal in the floor under the seat with a self tapping screw.
13. Put the seats back in the car, but before you install the seat bolts connect all the wires for each seat there should be a power wire, ground wire and a wire from the switch (and airbag wire) under each seat.
14. After all the wires are connected you can bolt the seats back in.
15. connect the battery and turn on the ignition and turn on the seat heaters to make sure every thing works. Once you found that everything is ok your done. Now you and your(wifes/girls/partners/mans) ass will be warm on those cold witer days.
I plan on installing in the rear seats as well, (My daughter is jealous now)